In the detergent industry enzymes have for more than 30 years been implemented in washing formulations. Enzymes used in such formulations comprise proteases, lipases, amylases, cellulases, as well as other enzymes, or mixtures thereof. Commercially most important enzymes are proteases.
Although proteases have been used in the detergent industry for more than 30 years, much remains unknown as to details of how these enzymes interact with substrates and/or other substances present in e.g. detergent compositions. Some factors related to specific residues of the proteases and influencing certain properties, such as oxidative and thermal stability in general, of the proteases have been elucidated, but much remains to be found out. Also, it is still not exactly known which physical or chemical characteristics are responsible for a good washing performance or stability of a protease in a specific detergent composition.
The currently used proteases have for the most part been found by isolating proteases from nature and testing them in detergent formulations.
At present at least the following proteases are known to be commercially available and many of them are marketed in large quantities in many countries of the world.
Subtilisin BPN' or Novo (available from e.g. SIGMA, St. Louis, U.S.A.), and Subtilisin Carlsberg, ALCALASE.RTM. (NOVO NORDISK A/S)) and MAXATASE.RTM. (Genencor).
A Bacillus lentus subtilisin, subtilisin 309, marketed by NOVO NORDISK A/S as SAVINASE.RTM.. A protein engineered variant of this enzyme is marketed as DURAZYM.RTM..
Enzymes closely resembling SAVINASE.RTM., such as subtilisin PB92, MAXACAL.RTM. marketed by Genencor Inc. (a protein engineered variant of this enzyme is marketed as MAXAPEM.RTM.), OPTICLEAN.RTM. marketed by SOLVAY et Cie. and PURAFECT.RTM. marketed by GENENCOR International.
A Bacillus lentus subtilisin, subtilisin 147, marketed by NOVO NORDISK A/S as ESPERASE.RTM.;
An increasing number of commercially used proteases are protein engineered variants of naturally occurring wild type proteases, e.g. DURAZYM.RTM. (Novo Nordisk A/S), RELASE.RTM. (Novo Nordisk A/S), MAXAPEM.RTM. (Gist-Brocades N.V.), PURAFECT.RTM. (Genencor International, Inc.).
Therefore, an object of the present invention, is to provide improved protein engineered protease variants, especially for use in the detergent industry.